Merge pull request #28733 from kamipo/dont_fallback_to_utf8mb3_after_mysql_8.0.0

Don't fallback to utf8mb3 after MySQL 8.0.0

3 files changed, 12 insertions, 10 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
index 71fa7b929c..c742799aab 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -64,14 +64,6 @@ module ActiveRecord
         end
       end
 
-      CHARSETS_OF_4BYTES_MAXLEN = ["utf8mb4", "utf16", "utf16le", "utf32"]
-
-      def internal_string_options_for_primary_key # :nodoc:
-        super.tap { |options|
-          options[:collation] = collation.sub(/\A[^_]+/, "utf8") if CHARSETS_OF_4BYTES_MAXLEN.include?(charset)
-        }
-      end
-
       def version #:nodoc:
         @version ||= Version.new(full_version.match(/^\d+\.\d+\.\d+/)[0])
       end
diff --git a/activerecord/lib/active_record/connection_adapters/mysql/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/mysql/schema_statements.rb
index 571edffec7..f9e1e046ea 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql/schema_statements.rb
@@ -45,7 +45,17 @@ module ActiveRecord
           indexes
         end
 
+        def internal_string_options_for_primary_key
+          super.tap do |options|
+            if CHARSETS_OF_4BYTES_MAXLEN.include?(charset) && (mariadb? || version < "8.0.0")
+              options[:collation] = collation.sub(/\A[^_]+/, "utf8")
+            end
+          end
+        end
+
         private
+          CHARSETS_OF_4BYTES_MAXLEN = ["utf8mb4", "utf16", "utf16le", "utf32"]
+
           def schema_creation
             MySQL::SchemaCreation.new(self)
           end
diff --git a/activerecord/test/cases/adapters/mysql2/schema_migrations_test.rb b/activerecord/test/cases/adapters/mysql2/schema_migrations_test.rb
index 605baa9905..251a50e41e 100644
--- a/activerecord/test/cases/adapters/mysql2/schema_migrations_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/schema_migrations_test.rb
@@ -18,7 +18,7 @@ class SchemaMigrationsTest < ActiveRecord::Mysql2TestCase
 
       ActiveRecord::SchemaMigration.create_table
 
-      assert connection.column_exists?(table_name, :version, :string, collation: "utf8_general_ci")
+      assert connection.column_exists?(table_name, :version, :string)
     end
   end
 
@@ -29,7 +29,7 @@ class SchemaMigrationsTest < ActiveRecord::Mysql2TestCase
 
       ActiveRecord::InternalMetadata.create_table
 
-      assert connection.column_exists?(table_name, :key, :string, collation: "utf8_general_ci")
+      assert connection.column_exists?(table_name, :key, :string)
     end
   end